Isolation transformer source
in [Repair]
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From: Phil Allison on 12 Jun 2010 10:43 "Dave Plowman " Rabid Pommy Nutcase" >> > Can anyone recommend a good isolation transformer for sale on-line? > >> ** What kind ?? > >> There are two: > >> 1. Galvanic isolation - for use on a service bench. > >> 2. Neutral conductor isolation. > >> Most you see offered for sale in the USA are of the *second* kind. > > > Surely an isolation transformer is just that... ** Shame it is not so in the USA - you Steaming Great Fuckwit ............... .... Phil
From: Dave Plowman (News) on 12 Jun 2010 13:12 In article <hv06fk$jkb$1(a)news-01.bur.connect.com.au>, Phil Allison <phil_a(a)tpg.com.au> wrote: > > Surely an isolation transformer is just that... > ** Shame it is not so in the USA > - you Steaming Great Fuckwit ............... But I'm not in the USA and neither are you. However, at least I know not to use bad language when visiting. If you'd ever known your parents they'd have likely taught you the same. -- *If at first you don't succeed, redefine success. Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: PlainBill47 on 12 Jun 2010 13:20 On Sat, 12 Jun 2010 10:32:04 -0400, "tm" <noone(a)msc.com> wrote: > >"JW" <none(a)dev.null> wrote in message >news:0qo616dhg4nsgshqjsia9l39venjef4bt6(a)4ax.com... >> >> Nice price. I'm working on a 1KW HP 6032A power supply (with outputs >> unloaded in this case, so I don't need *too* much current capability) and >> need to connect my scope to the hot side of a switching transformer - >> specifically the source and drains on the output FETs. >> >> Service manual: (3MB) >> http://www.home.agilent.com/agilent/redirector.jspx?action=ref&cname=AGILENT_EDITORIAL&ckey=1000000384-1%3Aepsg%3Aman&lc=eng&cc=US&nfr=-35687.384731 >> Page 113 shows the schematic of the FET board. >> >> With an isolation transformer, I *think* I would connect the scopes GND >> lead the source of Q1 and probe the it's gate to check the it, then move >> the scopes GND lead to Q3's drain lead to check it's gate drive. >> >> Given that, would that Ebay transformer be the right choice, and do I need >> to isolate (disconnect) the ground on the 6032A power supply under repair? >> >> Thanks. > >This is a "bad idea". Better to use a differential input and two probes. Do >you have a two channel scope with invert on channel 2? > >Tom > > That would be news to large numbers of electronics technicians who had to use an isolation transformer when servicing TVs and other 'live chassis' consumer electronics. There IS a reason the advice was 'to always keep one hand in your pocket'. PlainBill
From: Meat Plow on 12 Jun 2010 13:32 On Sat, 12 Jun 2010 10:20:10 -0700, PlainBill47 ǝʇoɹʍ: > On Sat, 12 Jun 2010 10:32:04 -0400, "tm" <noone(a)msc.com> wrote: > > >>"JW" <none(a)dev.null> wrote in message >>news:0qo616dhg4nsgshqjsia9l39venjef4bt6(a)4ax.com... >>> >>> Nice price. I'm working on a 1KW HP 6032A power supply (with outputs >>> unloaded in this case, so I don't need *too* much current capability) >>> and need to connect my scope to the hot side of a switching >>> transformer - specifically the source and drains on the output FETs. >>> >>> Service manual: (3MB) >>> http://www.home.agilent.com/agilent/redirector.jspx? action=ref&cname=AGILENT_EDITORIAL&ckey=1000000384-1%3Aepsg% 3Aman&lc=eng&cc=US&nfr=-35687.384731 >>> Page 113 shows the schematic of the FET board. >>> >>> With an isolation transformer, I *think* I would connect the scopes >>> GND lead the source of Q1 and probe the it's gate to check the it, >>> then move the scopes GND lead to Q3's drain lead to check it's gate >>> drive. >>> >>> Given that, would that Ebay transformer be the right choice, and do I >>> need to isolate (disconnect) the ground on the 6032A power supply >>> under repair? >>> >>> Thanks. >> >>This is a "bad idea". Better to use a differential input and two >>probes. Do you have a two channel scope with invert on channel 2? >> >>Tom >> >> > That would be news to large numbers of electronics technicians who had > to use an isolation transformer when servicing TVs and other 'live > chassis' consumer electronics. There IS a reason the advice was 'to > always keep one hand in your pocket'. > > PlainBill Serviced many GE VIR portables with a Sencore PR57 Powerite.
From: Dave Plowman (News) on 12 Jun 2010 13:35
In article <j7g716l13t96u9322qmqjiv8r5ppua3tdj(a)4ax.com>, <PlainBill47(a)yahoo.com> wrote: > That would be news to large numbers of electronics technicians who had > to use an isolation transformer when servicing TVs and other 'live > chassis' consumer electronics. There IS a reason the advice was 'to > always keep one hand in your pocket'. If using a proper isolating transformer, there will be no reference to ground even with a 'live' chassis. The only way to get an electrical shock is to touch both outputs from the transformer. -- *Why isn't there a special name for the back of your knee? Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound. |